An investigation of the reaction of metallic uranium with oxygen/nitrogen gas mixtures

The effects of variations in oxygen content as a mixed oxygen/nitrogen gas on the exothermic reaction of uranium were investigated in this work. Samples of metallic uranium with various specific surface areas and masses were reacted in a thermogravimetric analysis system at temperatures ranging between 323 K and 1273 K using gas mixtures 10%, 5%, 1%, or 0.5% oxygen in nitrogen. From the results it was concluded that the minimum oxygen content necessary for the onset of ignition is correlated to the specific surface area of the metallic uranium. The higher the specific surface area, the lower the percentage of oxygen is needed to trigger an ignition event. Within the experimental parameters evaluated here, ignition does not appear to occur for any specific surface area investigated below 1% oxygen content.